Here Peat talks about atropine / jimson weed, aka Datura stramonium, infamous for its hallucinogenic and intoxicating properties, but medicinal in this context:
"...the medical standard for a long time was to use muscle relaxant like atropine or jimson weed to relax the duct out of the gallbladder and then take olive oil to stimulate the contraction"
"But is there something, what did you say, Doc, you do before the gallbladder flush that is good to do to relax the muscles around the gallbladder?
The jimson weed. It works like atropine, very similar chemical. And that 50 to 100 years ago was recognized as very effective and safe, but the atropine, partly because drug culture used it for entertainment, it lost a lot of its medical use [...] A piece of leaf the size of your thumbnail sometimes was enough"